The present invention relates to a gas isolated switching device which performs a restriking surge suppressing function during switching operation thereof and, in particular, relates to a gas isolated switching device suitable for a gas isolated disconnecting switch.
In a power generating station and a power transforming station, for example, the suppression of a surge voltage due to a so called restriking surge, which is caused through circuit opening and closing operations such as by a disconnecting switch, is a very important problem.
Therefore, as disclosed, for example, in JA-A-61-66510 (1986) the restriking surge due to the switching operation of a gas isolated disconnecting switch is conventionally suppressed by mounting a cylindrical magnetic body around the outer circumference of a conductive body subjected to a high voltage.
In the above conventional art, no special consideration is made with respect to the influence of an increase in inductance (impedance) caused by the existence of the cylindrical magnetic body for suppressing the restriking surge, thereby an additional recovery voltage is likely to be applied between the contacts of a circuit breaker when a current, such as a fault current is interrupted by the circuit breaker. As a result the problem arises that in some instances the circuit breaker cannot interrupt such fault current. Namely, after such fault current passes through the zero point a high recovery voltage appears between the contacts of the circuit breaker because of the increased inductance in the system, as a result and the circuit breaker occurs and current interruption fails.